Brake for elevators



June 7.1927. g 1,631,340

M. ROHLFING BRAKE FOR ELEVATORS Original Fi1e d Dec. -.15, 1923 3 Sheets-Sheet 1 A 6 w I 6 I mum/ or? June 7, 1927.

. 1,631,340 J. M. ROHLFING BRAKE FOR ELEVATORS OrizinalFiled 1m. 15; 1923 a Sheets-Sheet 2 rrow/v0" June 7, 1927. r 1,631,340

. J. M. ROHLFING v BRAKE FOR ELEVATORS Original Fil ed Dec. 15. 1923 s Sheets-Sheet s.

tions 50 are alsoprovided with cylindrical chambers 60 which are open at their lower ends and communicate with-threaded openings at their upper ends which lead to the upper surfaces of the portions 50 and in which are threaded tubes 62 through which pass rodsr64. The rods 64 are provided With squared ends 66 which secure thereon followers68 having cylindrical portions 70 which slidably engage in the chambers 60 and .serve to guide the followers 68. The followers 68 are formed with inclined surfaces 72 which engage with corresponding ly inclined surfaces on the brake shoes 54. Mounted on the rods 64 in the chambers 60 are coil springs 74 which are confined between the followers 68 and followers 7 6 that engage either the upper ends of the chambers 60 or the lower. ends of the tubes .62. In other words, the springs 74 act-between the bracket wedges 50 and the upward counterweight connections so as to normally keep the brake shoes out of action. The rods 64 arethreaded. at their upper ends and have mounted thereon collars 78 and lock nuts 80 which serve toadjust the normal com.-

pression of the springs 74. Secured to the rods 64 are eyes 82 to which are fastened ends of cables 84 which pass over sheaves 86 pivotal-1y mounted adjacent the upper ends of the guides 1, the other ends of the cables 84 being secured to the counterweights 88 which travel in grooves formed by the outwardly projecting flanges 89 of of operation the springs will effect the startthe guides 1 and angles90 which are secured to the flanges 89 and have inwardly projecting flanges 92. The counter-weights 88 are formed with projecting portions which engage in back of the flanges 9.2. At theirlower ends the flanges 92 are connected by cross pieces 94 which serve as stops to limit the downward movement of the counterweights 88. r

' In operation the compression of the springs 74 is adjusted so that under normal conditions ing of the counter-weights 88 without further compression of the springs, the design of the parts being such that under this condition the brake shoes 54 do not bind against the inwardly projecting portion 5O of-the brackets 44 and the flanges 39 of the guides 1, thus permitting the elevator free movement in both directions. Should the hoisting cables 28 break while the elevatoris in an elevated position or should the motor be operated so as to cause the elevator to drop and accelerate at a rate in excess of the desired rate, the pull due to the inertia of the counterweights 88 will be greater than that for which the springs 74are adjusted, and the rods 74 and associated parts will be drawn upward, so that a further compression of the springs 74 will take place. Asthe springs 74 are compressed further in rethe elevator, the downward movement of the elevator tending to increase the braking action of the shoes as thus actuated. After the brakes have been applied either by the breaking of the cables 28 or by excessive speed due to the operation of the motor 24, the operation of the motor to raise the elevator will raise the brackets 44 and the ta pered portions 50 between the brake shoes 54 and destroy the braking action of the shoes so that after thebrakingaction has taken place it is merely necessary to operate the elevator in a. direction to raise it in order to release the brake shoes from their wedging engagement with the guides 1 and the tapered portions 5-0 on the brackets 44.

What is claimed is:

1. An elevator braking mechanism prising weight retracted oppositely and latorally movable wedge elements to engage opposed walls of an elevator guide, a head disposed below the wedge elements and raised vertically against the latter to cause them to engage the elevator guide incident to un-- safe acceleration of the elevator. i r

2. In an elevator safety attachment, coacting slidably connected wedge'eleinents carried by the elevator and movable in one of the guides therefor, and normally held out of contact of such guide, but moved into gripping contact with the guide by the sliding wedge action of the wedge elements when the elevator travels at an unsafe velocity.

3. In combination, an elevator, co-acting slidably connected wedge elements attached to opposite sides of the elevator, and operabl'e'to frictionally engage parts of the elevator shaft to brake the movement of the elevator when thelatter travels at an unsafe rate of speed.

4. An elevator braking mechanism comprising an upright structure with opposed internal surfaces, brake shoes between said surfaces, and expanding means between the brake shoes for forcing them apart against the surfaces, in response to acceleration of the elevator.

5. An elevator braking mechanism co1nprising an upright structure with opposed internal surfaces, brake shoes between said surfaces, a down-tapered expanding wedge between said brake shoes, and means responsive'to acceleration of the elevator for raising said brake shoes and thus causing their expansion against the surfaces by the wedge, v 6. An elevator braking mechanism coming said flanges, and brake'means carriedby 2 prising a guideway with opposed internal surfaces, guide, means for the elevator externally embracing said guideway, and brake means carried by the elevator for acting between said opposed surfaces.

7. An elevator braking mechanism comprising a guide member with juxtaposed flan es rude means for the elevator en a the elevator for acting between the flanges.

8. An elevator braking device comprising an elevator bracket, brake shoes and actuat- 111g means therefor carried by said bracket an upward extending counterweight connec-' wedge including an upward extending coun-, ter weight connection, and an adJustable spring mounted on said wedge for normally keeping the brake shoes out of action.

10. In a device of the class described, an elevator, guides for said elevator, supporting brackets for said elevator, counter-weights, flexible means connected to' said counterv weights, followers connected to said flexible means, springs interposed between said followers and brackets, and braking means for said elevator operated by said followers upon the yielding of said springs. Y

11. In a 'device of he class described, an

elevator, guides for said elevator, supporting brackets for said'elevato-r having surfaces.

inclinedtosaid guides, counterweights, flexible means connected to said counter-weights and having connections through said brackets, followers carried by said connections, springs interposed between said followers and brackets,and brake shoes shiftable by I said followers into wedging engagement with said inclined surfacesand guidesrupon the yielding of said springs.

12. An elevator safety catch, including a plurality of interfitting members, one of which being arranged to be rigidly attached to part of an elevator, and having longitudinal slidable engagement with 'the others, and means operable by the acceleration of the elevator to expand such interfitting elements into frictional engagement with a stationary object arranged along the path of movement of the elevator.

13. An elevator safety catch, including a wedge element to be rigidly attached to one side of an elevator-and movable verticallyv in the guide thereof, brake shoes upon opposite sides of the wedge element, and having wedge surfaces co-incident to the wedge surface of the wedge element and normally ar ranged out of contact with the guide, a head slidably associated with the wedge element and upon which the brake shoes rest, and means operable for the unsafe acceleration of the elevator for raising the head and thereby shift the brake shoes along the wedge element to cause the the guide.

In witness whereof I have hereunto set my hand.

latter to expand against JOHN M. ROHLFING. 

